Clouds, unstable Loop Current making oil spill prediction difficult

It's cloudy over the Gulf of Mexico today, so it is difficult to tell how far into the Loop Current the Deepwater Horizon oil has penetrated using visible satellite imagery. Satellite imagery yesterday from NASA's MODIS instrument confirmed that a tongue of oil moved southeast from the Deepwater Horizon oil spill and entered the Gulf of Mexico's Loop Current. However, Synthetic Aperture Radar imagery from the European Envisat satellite posted at ROFFS Ocean Forecasting Service shows that while some of the tongue of oil that entered the Loop Current appears to be circulating southwards towards the Florida Keys, perhaps 80% of the oil in this tongue is caught in a counter-clockwise circulating eddy along the north side of the Loop Current. This oil may eventually circulate around and enter the Loop Current, but not for at least three days.

Figure 1. Oil spill forecast for this Thursday night as simulated by the 6pm EDT Monday May 17 runs of the Navy Gulf of Mexico HYCOM nowcast/forecast system and the Global HYCOM + NCODA Analysis from the HYCOM Consortium. See the University of South Florida Ocean Circulation Group website for more information. There are considerable differences between the two models, due in part to the fact that they have much different depictions of the sea surface temperatures (SSTs) and ocean currents at the beginning of their runs. The warm Loop Current is visible as the red colors of the SST field that form a heart-shaped area in the Gulf.

How long will it be until oil reaches the Keys?Once oil gets into the Loop Current, the 1 - 2 mph speed of the current should allow the oil to travel the 500 miles to the Florida Keys in 5 - 10 days. Portions of the Loop Current flow at speed up to 4 mph, so the fastest transport could be 4 - 5 days.

How much oil has made it into the Loop Current?According to the latest trajectory forecasts from NOAA, the tongue of oil flowing southwards has, at most, "light" concentrations. The oil will grow more dilute as it travels the 500 miles to the Florida Keys, and most of the oil appears to be caught in a smaller counter-clockwise rotating eddy on the north side of the Loop Current. My present expectation is that the oil entering the Loop Current this week will cause only minor problems in the Keys next week. However, there is a lot of uncertainty regarding how much oil will get to the Keys, and we cannot rule out the possibility of an ecological disaster in the fragile Keys ecosystem.

How is the Loop Current changing?The Loop Current has been highly chaotic and unstable over the past week, making it difficult to predict how the ocean currents near the spill will behave. According to ROFFS Ocean Fishing Service, which has done a tremendous job tracking the spill, the Loop Current surged 7 - 10 miles northward Sunday and Monday. The Loop Current has gotten more contorted since Friday, and may be ready to cut off into a clockwise-rotating Loop Current Eddy. This process occurs every 6 - 11 months, with the clockwise-rotating ring of water slowly drifting west-southwest towards Texas. The last eddy broke off ten months ago, so the Loop Current is due to shed another eddy in the next few months. The latest 1-month forecast from the U.S. Navy does not predict an eddy forming, but these forecasts are not very reliable. If a Loop Current Eddy does break off, oil getting entrained into it might orbit the center of the Gulf of Mexico for many months inside the eddy. However, this eddy will probably reattach and detach from the main Loop Current flow for at least a month following when it breaks off, so oil will continue to flow through the Keys during this initial month.

When will the flow of oil into the Loop Current shut off?Winds over the oil spill location are expected to be light and onshore at 5 - 10 knots through Saturday. This means that the chaotic contortions of the Loop Current will primarily control how much oil gets into it, making it difficult to predict when the flow will shut off. The long range (and thus unreliable) forecast for next week from the GFS model calls for a continuation of light winds over the eastern Gulf of Mexico. Thus, the flow of oil into the Loop Current could occur intermittently for several weeks.

Who besides the Keys are at risk next week from the Loop Current oil?As I discussed in an earlier post, the coast of Southwest Florida from Tampa Bay to the Everglades is a "Forbidden Zone" for surface-based transport of ocean water to the coast, and is probably not at risk from this week's Loop Current oil. The northwest coast of Cuba east of Havana and the coast of Southeast Florida from the Keys to West Palm Beach are at the most risk. The western shores of the western-most Bahama Islands and the U.S. coast north of West Palm Beach northwards to Cape Hatteras are at slight risk. It would likely take ocean eddies 2 - 9 weeks to transport the oil to these locations, and the oil would probably be so dilute that ecosystem damage would probably be minor, at most. At this point, I see no reason for cancellation of vacation plans to any of the beach areas that may potentially be affected by the oil.

What is happening to the plumes of oil at depth?Two research missions over the past week have detected substantial plumes of oil at depth, moving to the southwest. The deepest of the these plumes, near the site of the blowout at 5,000 feet depth, is in a region of slow ocean currents and has not moved much. At depths closer to the surface, the currents get stronger, and oil within a few hundred feet of the surface--if there is any--could potentially have been dragged into the Loop Current. At this point, we don't have a very good picture of how much oil is at depth and where it might be headed.

The tropicsFor those of you interested in a detailed look at the early season tropical weather outlook, consult the excellent wunderblogs of StormW and Weather456, who are now featured bloggers for the coming hurricane season. We have some models predicting a possible subtropical storm off the U.S. East coast next week, but this does not appear to be a significant concern for land areas at this time. More concerning is the possibility that an area of disturbed weather will develop across the Western Caribbean late next week. While wind shear will likely keep anything in the Western Caribbean from developing, several models are predicting that this disturbance may bring major flooding rains to earthquake-ravaged Haiti late next week.

Coast Guard Under 'BP's Rules'Kelly Cobiella reports that a CBS News team was threatened with arrest by Coast Guard officials in the Gulf of Mexico who said they were acting under the authority of British Petroleum.

The US Coast Guard is working under the authority of BP?Well, I'll be dammed...

Which party believes in "drill baby drill" and low regulations? They really need to take responsibility. I will accept there apology if they admit they are wrong. Blaming others who know how capitalism works and realize it needs to be regulated is totally insane.

Coast Guard Under 'BP's Rules'Kelly Cobiella reports that a CBS News team was threatened with arrest by Coast Guard officials in the Gulf of Mexico who said they were acting under the authority of British Petroleum.

"When CBS News tried to reach the beach, covered in oil, a boat of BP contractors with two Coast Guard officers on board told us to turn around under threat of arrest. Coast Guard officials said they are looking into the incident."

What really stands out to me is the upper ridge over the Caribbean in 2005. This was essentially the same for all of May that year, with anomalous upper easterlies across the Caribbean due to anomalous ridging at 200mb over the eastern Caribbean.

Also of note are the anomalous upper westerlies, and hence higher wind shear, in the eastern tropical Atlantic, which to some extent continued through the peak of the season, contributing to the almost nonexistant Cape Verde season in 2005.

"When CBS News tried to reach the beach, covered in oil, a boat of BP contractors with two Coast Guard officers on board told us to turn around under threat of arrest. Coast Guard officials said they are looking into the incident."

At 910 PM CDT... National Weather Service Doppler radar and stormspotters were tracking a tornado. This tornado was located 14 mileswest of Conlen... or about 15 miles north of Dalhart... moving east at30 mph.

* Locations impacted include...Conlen...

Precautionary/preparedness actions...

If in Mobile homes or vehicles... evacuate them and get inside asturdy shelter. If no shelter is available... lie flat in the nearestditch or other low spot and cover your head with your hands.

At 910 PM CDT... National Weather Service Doppler radar and stormspotters were tracking a tornado. This tornado was located 14 mileswest of Conlen... or about 15 miles north of Dalhart... moving east at30 mph.

* Locations impacted include...Conlen...

Precautionary/preparedness actions...

If in Mobile homes or vehicles... evacuate them and get inside asturdy shelter. If no shelter is available... lie flat in the nearestditch or other low spot and cover your head with your hands.

Do you all remember Hurricane Alberto in 1982? I remember the system formed into a Tropical Depression on the morning of June 2nd. I went to school and when I came home in the afternoon I turned on WeatherBand to find out we had Hurricane Alberto approaching the SW coast of Fla. Memories...

Quoting atmoaggie:Hmm, mom is prolly not a good test subject for that as she was a lot crazy before she moved up there.

Then, again, doesn't it take at least a little crazy just to move there? That perception might be skewed by the population (or lack thereof)...

I was in WY back in 2002 and before that in 1987 (I think). I remember how amazing the change in landscape is once you get past the plains. It was amazing to know that the city I lived in had a larger population than the Entire State when I was up there in '87 . I remember some town had a summer population of 6 and a winter pop of 0.

My cousins friend spent a summer there and I recall that he was slightly off his rocker also... He always spoke of WY new amendment to the constitution 'As the right to arm bears..'

There is no archive for those maps, but from what I can tell it wasn't too bad at this particular time last year. Looks like there may have been a minor outbreak in the central-eastern Atlantic. I wouldn't know exactly how much SAL this map shows....there are others here with better sites for aerosols than I have.